During scanning of a photoconductive surface, such as an x-ray plate, with a focused laser beam, an electrical signal is generated which represents an image. Variations in laser light intensity during scanning introduce errors in the measured signal and in the density of the reproduced image. These variations in laser light intensity are known collectively as laser noise. Laser noise, manifested as variations of light output intensity with time, is a characteristic of both gas and semiconductive lasers. This laser noise, and other signal errors, cause the modulation transfer function of the system to be degraded.